Effects of acridine dyes and other substances on growth, lysis and toxicity of Anabaena flos-aquae

Abstract

Growth of Anabaena flos-aquae NRC-44-1 in the presence of sub-lethal concs of acriflavine was generally better than that in acriflavine-free medium and the beneficial effect was mostly due to inhibition of lysis to which the alga is highly susceptible during the post-alogrithmic phase of growth. Some photodestruction of acriflavine apparently occurred during incubation. The administration of a cumulative series of acriflavine does at different stages of the growth curve did not result in any significant improvement in yield or inhibition of lysis. During the course of 10 successive subcultures in media containing acriflavine, proflavine or acridine orange, no adaptation to grow in concs higher than these tolerated by untreated alga occurred; indeed, after 6 subcultures in acriflavine, the alga was more prone to early and rapid lysis than before. Lysis in this alga appears to be an autolytic process rather than virus-induced. A study of the effect of pre-and post-treatment with acriflavine on sensitivity of the alga to ultraviolet radiation demonstrated that in basal as well as acriflavine media the growth of acriflavine pretreated material was better than that of untreated alga both as regards the duration of the lag-phase and the maximum optical density. The rates of incorporation of tritiated thymidine in untreated suspensions were identical with those treated with mitomycin C. these experiments, as well as electron microscopy, failed to reveal any virus particles in the alga. It is tentatively concluded that toxicity is not controlled by extrachromosomal genetic determinants.